1. Technical Field
The present disclosure relates to a radar apparatus and a running vehicle sensing method.
2. Description of the Related Art
Techniques for sensing an object (target) by a radar apparatus are disclosed in, for example, Japanese Unexamined Patent Application Publications Nos. 60-122381 and 2011-180030.
The radar apparatus disclosed in Japanese Unexamined Patent Application Publication No. 60-122381 samples a radar received wave (receive signal) including a reflected wave from an object and ground clutter as a reflected wave from the ground for each range bin which is a unit of processing for a search target distance and obtains a Doppler component of the receive signal for each range bin. The radar apparatus disclosed in Japanese Unexamined Patent Application Publication No. 60-122381 then compares the magnitude of a variation in a power value (Doppler component) of a receive signal in the Doppler frequency domain with a predetermined threshold. Even in the presence of effects of ground clutter, such a technique is capable of sensing as an object if the power of a certain frequency component is higher than that of a surrounding frequency component in the Doppler frequency domain.
The radar apparatus disclosed in Japanese Unexamined Patent Application Publication No. 2011-180030 calculates phase differences of peak frequencies in beat signal received by a plurality of receiving antenna elements. The radar apparatus disclosed in Japanese Unexamined Patent Application Publication No. 2011-180030 also calculates a direction of an object on the basis of the calculated phase differences between the plurality of receiving antenna elements and the relative positional relationship among the plurality of receiving antenna elements. Such a technique is capable of sensing a plurality of objects located in different directions.